Change checkout form for prestashop page

Need to make changes to the checkout form of prestashop. It should pe a one page checkout style with single Checkout button (without any autenthification or save button). Only 10 custom fields (like name, address ..). No coupon code, no shipping fee estimator. IMPORTANT: need to have two checkout box at the begining to select if the customer is private customer or it's a company, and acording to this value it should be displayed the fields below (for company there are other fields). All the checkout form content must be send in the transactional email.